A three-flute drill with a cutting fluid supply hole frequently used as a tool for drilling having a shaft-shaped tool main body provided with three cutting edges at its distal end, a flute portion having three discharge flutes formed in the shaft-shaped tool main body for discharging chips generated by the three cutting edges, and a cutting fluid supply hole for supplying cutting fluid toward the cutting edges through an inside of the flute portion.
Drills described in Patent Documents 1 to 3 are examples thereof. Since oily or aqueous cutting fluid is supplied near the cutting edges through the cutting fluid supply hole in the vicinity of cutting points of the respective cutting edges, these three-flute drills suppress a temperature increase at machining points and prevent chipping, damaging, breakage, and burning of the cutting edges, flanks thereof, corner portions, and chisel edges as depicted in FIGS. 15, 16, 17, and 18 to enhance the durability of the drills. Particularly if a work material is a difficult-to-cut material such as stainless steel and titanium alloy, such an effect is expected.